//Imports packages
import java.awt.*; //Used create to buttons
import java.awt.event.*; //Used create an event
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;

import javax.swing.*;

import java.text.DecimalFormat; //Used to import decimal format for money

//Action listener
public class MortgageCalculator extends JPanel implements ActionListener, ItemListener
{

   //Variables
   protected JComboBox MortIntRate;
   protected JLabel lblprincipal, lblinterestRate, lblTerm, lblmonthlyPayment;
   protected JButton calculate, Reset, exit;//New button exit


   protected JTextField principal, interestRate, Term, monthlyPayment, mortgagecalculater;
   protected TextArea MortPayResults;

   public MortgageCalculator()

   {

      String[] comboItems = {"5.35", "5.50", "5.75", "Custom"};//Interest rates used in program creating a combo box


      //Label are defined here,used to creates labels and fields

      lblprincipal = new JLabel("Principal Amount:");
      principal = new JTextField("", 4);
      lblinterestRate = new JLabel("Interest Rate:");
      interestRate = new JTextField("", 3);
      interestRate.setEditable(false);
      lblTerm = new JLabel("Term:");
      Term = new JTextField("", 3);
      lblmonthlyPayment = new JLabel("Monthly Payment:");
      monthlyPayment = new JTextField("", 5);
      MortIntRate = new JComboBox(comboItems);
      mortIntPrevSel = (String) MortIntRate.getSelectedItem();
      interestRate.setText((String) MortIntRate.getSelectedItem());
      MortIntRate.addItemListener(this);

      MortPayResults = new TextArea(20, 65);

      //Create action buttons
      calculate = new JButton("Calculate"); //Create button used to calculate mortgage payment
      calculate.setActionCommand("GO");

      Reset = new JButton("Reset"); //Create button used to reset data from the fields
      Reset.setActionCommand("Reset");

      exit = new JButton("Exit");//new
      exit.setActionCommand("Exit");//new



      //Activate buttons
      calculate.addActionListener(this);
      Reset.addActionListener(this);
      exit.addActionListener(this);//new

      //Add labels and fields

      add(lblprincipal);
      add(principal);
      add(lblinterestRate);
      add(interestRate);
      add(MortIntRate);
      add(lblTerm);
      add(Term);
      add(lblmonthlyPayment);
      add(monthlyPayment);
      add(MortPayResults);
      add(calculate);
      add(Reset);
      add(exit);//new

   }
   public void actionPerformed(ActionEvent e)// Action event occurs here
   {
      if ("GO".equals(e.getActionCommand()))
      {
         CalculateMortgage();
      }
      else
      {
         principal.setText("");
         interestRate.setText("");
         Term.setText("");
         monthlyPayment.setText("");
         MortPayResults.setText("");

      }
   }

   public void CalculateMortgage()
   {
//      interestRate.setText("" + (String) MortIntRate.getSelectedItem());
      double dblprincipal = Double.parseDouble(principal.getText());
      double dblInterestRate = Double.parseDouble(interestRate.getText());

      //Handle the condition.
      if (dblInterestRate == 5.35)
         Term.setText("7");
      else if (dblInterestRate == 5.50)
         Term.setText("15");
      else if (dblInterestRate == 5.75)
         Term.setText("30");

      //Currency is set here
      int intTerm = Integer.parseInt(Term.getText());
      DecimalFormat money = new DecimalFormat("$0.00");

      double MonthlyPayment;
      double InterestPaid;
      double PrincipalBal;
      double temp;
      int Months;
      double MIntRate = dblInterestRate / 100;
      int MTerms = intTerm * 12;
      Months = MTerms;

      //Formulas
      MonthlyPayment = (dblprincipal * (MIntRate / 12)) / (1 - 1 / Math.pow((1 + MIntRate / 12), MTerms));

      //Converts Monthly Payment to decimal format
      monthlyPayment.setText("" + (money.format(MonthlyPayment)));

      MortPayResults.append("Month No.\tMonthly Payment\t\tLoan Balance\t\tInterest Payment\n");

      for (int counter = 0; counter < MTerms; counter++)
      {
         temp = (1 - 1 / Math.pow((1 + MIntRate / 12), Months));
         InterestPaid = MonthlyPayment * temp;
         dblprincipal = (dblprincipal - MonthlyPayment + InterestPaid);
         MTerms = MTerms--;
         Months--;

         MortPayResults.append((counter + 1) + "\t\t" + (money.format(MonthlyPayment) + "\t\t" + (money.format(dblprincipal) + "\t\t" + (money.format(InterestPaid) + "\n"))));
         MortPayResults.setCaretPosition(0);
      }

   }
   //GUI is created in this section
   private static void createAndShowGui()
   {
      JFrame frame = new JFrame("Multiple Mortgage Calculator");

      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

      //Frame is setup

      MortgageCalculator myCalculator = new MortgageCalculator();
      myCalculator.setOpaque(true);
      frame.setContentPane(myCalculator);

      frame.pack();
      frame.setVisible(true);


   }

   public static void main(String[] args)
   {
      javax.swing.SwingUtilities.invokeLater(new Runnable()
      {
         public void run()
         {
            createAndShowGui();
         }
      }

      );

   }

//Get interest rates here
   public void itemStateChanged(ItemEvent e)
   {
      if(e.getSource() instanceof JComboBox)
      {
         JComboBox cb = (JComboBox) e.getSource();
         String str = (String) cb.getSelectedItem();
         if(str.equals("Custom"))
         {
            interestRate.setEditable(true);
            interestRate.setText("");
         }
         else
         {
            interestRate.setEditable(false);
            interestRate.setText(str);
         }

      }
   }

private String mortIntPrevSel;

}